This invention relates to tape transport apparatus and, more particularly, to a variable speed tape transport apparatus wherein tape can be transported at a first normal speed or at a second, higher normal speed and, moreover, the tape can be selectively transported at a fast speed which is at least equal to the higher normal speed.
In conventional tape recording devices, it is known that tape generally is transported at a relatively lower speed past a record/playback head to permit information to be recorded on and played back from the tape. In the event that the tape is to be rewound or advanced to a selected position therealong, the tape preferably is transported at a relatively higher speed. With the advent of the tape cassette wherein tape is housed in a cartridge and is adapted to be transported past apertures in the cassette housing from, for example, a supply reel to a takeup reel, the tape recording and playback apparatus is provided with controls to selectively attain normal forward motion of the tape, rapid rewind motion of the tape and fast-forward motion of the tape, all within the cassette housing.
In general, the quality of sound recorded on magnetic tape is, to a large extent, related to the transport speed of the tape. That is, there is a lower tape speed limit below which the fidelity of reproduced sound is degraded. This means that, in the manufacture and construction of a tape cassette, the amount of tape, or recording time, of the cassette should be balanced with the desired quality of the reproduced sound. This characteristic is of particular importance in portable cassette recording machines. In such machines, it is desirable to maximize the recording time capacity of each cassette, while minimizing the size of both the cassette and recording apparatus.
The foregoing considerations have resulted in various standardized criteria in the design of tape cassettes and cassette recording apparatus. That is, tape transport systems used in many cassette recording devices are adapted to transport the tape at a given normal speed which permits a relatively high quality of sound reproduction. This tape speed for the reproduction of sound from pre-recorded cassettes is, of course, equal to the tape speed used during the recording process. Of course, for cassette recording devices which are capable of recording audio information on tape, the same tape speed is used both for recording and playback operations. However, in some instances, it is desirable to use the cassette recording apparatus in certain situations wherein high fidelity sound reproduction is not as important as increasing the recording capacity. In these situations, it is preferred to transport the tape at a relatively lower speed for sound recording and reproduction. Conversely, in other situations wherein the quality of reproduced sound is more important than the recording capacity, it is preferred to transport the tape at a relatively higher speed during sound recording and reproduction.
Accordingly, it is one object of this invention to provide a variable speed tape transport apparatus wherein tape can be transported for sound recording and reproduction at a selected one of plural tape speeds. Where such a tape transport apparatus is to be used in, for example, a portable recording/playback device, the tape transport apparatus should be of relatively simple construction.
Also, where the tape transport apparatus is to be used with, for example, tape cassettes having a uniform outward appearance, it is preferred to provide soem indication of the tape speed which was used for recording. This, of course, is helpful in selecting the playback speed which must be equal to the recording speed for intelligible reproduction. Although such indications may be of the type that is sufficient to apprise an operator of the recording/playback apparatus, it is preferable to provide for the automatic sensing of such indications so that the appropriate tape speed may be automatically selected. This avoids possible confusion and erroneous operation of the recording/playback apparatus for the operator.